Help with billboarding

Hello everyone. I'm trying to use 2D sprites in a 3D game, but I'm having issues with the billboarding. I've got a bunch of different colored circles that I'm trying to use for a base fairy design (ignoring particle effects and whatnot for now) but the current code that I'm using starts to get warped as it approaches the edge of the screen, and I think if there are several sprites close together it also gets thrown off.

I've tried a number of the other threads on here, and my google-fu has failed me. So far this is the closest script that I can find, also including a few screenshots of the issue. Let me know if you've got any ideas, but even if you don't then thank you for reading this. (also the farmer PC is just a placeholder while the MC gets designed)

https://cdn.discordapp.com/attachments/353422958984953857/639156395115282452/unknown.png https://cdn.discordapp.com/attachments/353422958984953857/639156776213676044/unknown.png

 public class Billboard : MonoBehaviour
 {
     LateUpdate() 
     {
         transform.LookAt(Camera.main.transform.position, -Vector3.up);
     }
 }